a-a a-b a-c aaa aab aac aad aah aak ab- aba abb abc abd abh abk ac- aca acb acc acd ach ack ad- ada adb adc add adh adk aha ahb ahc ahd ahh ahk aka akb akc akd akh akk baa bab bac bad bah bak bba bbb bbc bbd bbh bbk bca bcb bcc bcd bch bck bda bdb bdc bdd bdh bdk bha bhb bhc bhd bhh bhk bka bkb bkc bkk c-- caa cab cac cad cah cak cba cbb cbc cbd cbh cbk cca ccb ccc ccd cch cck cda cdb cdc cdd cdh cdk ch- cha chb chc chd chh chk cka ckb ckc ckd ckh daa dab dac dad dah dak dba dbb dbc dbd dbh dbk dca dcb dcc dcd dck dda ddb ddc ddd ddh ddk dh- dha dhb dhc dhd dhh dhk dka dkb dkc dkk haa hab hac had hah hak hba hbb hbc hbd hbh hbk hca hcb hcc hcd hch hck hda hdb hdc hdd hdh hdk hha hhb hhc hhd hhh hhk hka hkb hkd hkh hkk ka- kaa kab kac kad kah kak kba kbb kbc kbd kbh kbk kca kcb kcc kcd kch kck kda kdb kdc kdh kdk kha khh khk kkb kkc kkh kkk